End effectors may be mounted on robotic arms to carry out any of various operations on workpieces. For example, in the aerospace industry, an end effector may include clamping and drilling tools for forming holes in aircraft subassemblies. The robotic arm moves the end effector to a position in which a pair of opposing clamping jaws are disposed on opposite sides of the workpiece. The jaws are closed to clamp the workpiece, following which a drilling operation may be performed.
A robotic end effector of the type described above requires the robot to position the clamping jaws around the workpiece with relative accuracy. Inaccurate positioning of the jaws may result in one of the jaws engaging and applying force to the workpiece before the other jaw is fully closed. This uneven application of force may result in slight displacement of the workpiece, or excessive force being applied to the workpiece, producing less than optimum results. In addition to the possibility of inaccurate placement of the robotic arm, part-to-part variations in the workpiece or inaccurate positioning of the workpiece in fixturing may also result in the workpiece not being accurately positioned between the clamping jaws. Thus, current end effectors and clamping techniques rely on relatively accurate positioning of the end effector, as well as accurate location of the workpiece.
Accordingly, there is a need for a robotic end effector and clamping method that overcome the problems mentioned above, and allow clamping a workpiece where a robotic arm may not be precisely positioned or variations may occur in the workpieces or their positioning. Embodiments of the present disclosure are intended to provide a solution to these problems.